1. Field of the Invention
The present application generally relates to medical devices, systems and methods, and more particularly relates to devices, methods and systems for reducing the risk of surgical site infections.
Formerly known as “wound infection,” surgical site infection (SSI) is generally defined by the Centers for Disease Control and Prevention (CDC) as an infection in the area of the surgical incision that occurs within 30 days of an operation. The CDC further subdivides SSI into two groups. The first group includes superficial and deep “incisional” SSI (ISSI). The second group includes “organ/space” SSI. These two groups appear to be somewhat different phenomena with respect to etiology, physiology, pathogenesis, clinical presentation, and treatment. Of note, the term “wound infection,” as currently used in the medical colloquium, refers to and is more compatible with ISSI, as opposed to organ/space SSI.
ISSI affects approximately 3-4% of the more than 30 million operations performed in the U.S. each year. Although the state of current medical care has minimized the mortality associated with ISSI, the morbidity and associated costs to the healthcare system remain significant. On average, ISSI extends the length of an inpatient hospital stay by 9 days, as well as introduces the added necessity and costs of outpatient wound management, which can reach upwards of 10,000-45,000 U.S. dollars per patient. Estimates of the aggregate annual burden to the U.S. healthcare system exceed five billion U.S. dollars.
The diagnosis of SSI is usually made by a physician and is usually based on the clinical finding of various signs and symptoms of infection at the incisional site, such as pain, tenderness, swelling, redness, warmth, and purulent drainage. Various ancillary tests, such as microbial cultures or radiographic exams (e.g., computed tomography scans), can aid in the diagnosis. The length of treatment can extend for weeks or even months.
Obese patients are particularly vulnerable to developing wound infections, with a two to three fold increased risk relative to the overall population. This is at least partially due to the poor vascularization of subcutaneous fat, reducing the delivery of prophylactic intravenous (IV) antibiotics to the incision site. Furthermore, subcutaneous fat is an excellent media for the incubation of bacterial infection. With increasing rates of obesity worldwide, this will only further compound the problem of ISSI.
Another risk factor for the development of ISSI is the type of surgical procedure performed. For example, colorectal surgeries are associated with a baseline infection rate of 15-20%. This is a result of the contaminated nature of the procedure, as fecal contents are often released into the operative field when colon, small bowel, or rectum is cut. Furthermore, colorectal surgery involves the manipulation and removal of large organs (e.g. the colon), and consequently, large incisions are often required to perform the procedures. ISSI risk is directly correlated with the size of surgical incision used to perform the case. These risks are further compounded when combined with other risk factors such as obesity. For example, the rates of wound infections in obese patients undergoing colorectal surgery increase to upwards of 33%, representing a major burden to the healthcare system in terms of the quality and cost of services.
Prior surgical instruments and methods have been developed with the aim of reducing wound infections, yet the scope of the problem has not been reduced. Some solutions have addressed the issue by implanting degradable sponges in the incision to combat the development of wound infections post-operatively. However, this approach led to increases in wound infection rates, as the immune system reacts poorly to the implant because the implant is a “foreign body.”
Surgeons have previously irrigated the incision or wound margins with fluids such as saline and/or antibiotics, but the practice has proved to be disruptive to surgical progress, difficult to implement and standardize in surgical practices, and consumes valuable time, increasing patient risk and increasing operative costs.
Barrier wound protectors have also been employed to prevent the egress of bacteria into the incision, but this is merely a passive approach, and considering the barrier protection must be removed to complete the operation, the incision is inevitably exposed to the infectious contents contained within the surgical field. Additionally, wound protectors may be difficult to manipulate, especially when positioned in the surgical field. A further drawback is that the barrier can also trap bacteria onto the wound surface, allowing bacteria to proliferate in the wound space.
Considering the significant morbidity and cost associated with SSI, it is desirable to provide a way to reduce the occurrence of SSI that is superior to the limitations of currently available commercial devices.
In addition to the challenges mentioned previously, in select situations, a key aspect of surgery involves obtaining adequate surgical “exposure,” or alternatively, adequate visualization and access to target anatomical landmarks and structures to be operated upon. To achieve proper exposure, surgeons can use a variety of surgical retractors generally configured to maximize the opening of the incision and create space within the operative region (e.g. chest, abdomen, orbit, neck, and groin) to facilitate the completion of the surgical procedure.
One surgical retractor used in abdominal surgery involves a top ring, bottom ring, and a flexible tubular sheath (also referred to as a pliable membrane) disposed between the top and bottom rings. In numerous embodiments, manipulation of the top ring in a variety of ways (e.g., by rolling the sheath around the top ring) is sometimes effective to shorten the sheath length and retract the edges of the incision. In many cases, such surgical retractors incorporate barrier wound protection, the potential disadvantages of which have already been described.
The drawbacks of surgical retractors described in currently available commercial devices are numerous. They can be difficult to use, requiring additional time and the manual application of forces that may be difficult for surgeons to apply in an operative setting. They may require more than one person to operate, decreasing focus on the operative field, increasing operative time and personnel costs. In addition, due to the unpredictable nature of a surgical operation, the initial incision size may not be ideal, thus requiring lengthening during the course of the procedure. Many commercially available surgical retractors do not allow for an increase in incision size with the device in situ. Moreover, currently available commercial surgical retractors may employ a design requiring a variety of sizes to accommodate the wide range of incision sizes encountered during surgery. As a result, hospitals may have to stock a range of device sizes, and often multiple devices are used in a single procedure as the size of the incision may be increased. Using multiple devices may result in increased healthcare costs, surgery duration, and infections.
As noted previously, it may be advantageous to incorporate the combined functions of fluid delivery and fluid removal into a retraction device configured to reduce the risk of surgical site infections. Proposed embodiments of such a device may provide fluidic functions that are generally disposed along or near a pliable membrane, and that are configured to provide barrier wound protection (preventing direct contamination of the wound edges) and retraction of the surgical wound to permit visualization and access to the surgical site. U.S. patent application Ser. Nos. 13/736,888 and 13/736,904 disclose further details about such a device, the entire contents of which are incorporated herein by reference. Methods of using such a device are also disclosed in U.S. patent application Ser. No. 13/736,785, the entire contents of which are incorporated herein by reference. Additional disclosure about various features which may be used in such a device are disclosed in U.S. patent application Ser. No. 14/209,393, the entire contents of which are incorporated herein by reference. While these embodiments are preferred due to their ability to accommodate a range of incision sizes, their ability to increase the size of the incision without removing the retraction device from the surgical field, and their speed of use, among other benefits, it may be beneficial to implement fluid delivery and optionally fluid evacuation with other commercially available retractors. One such exemplary commercial retractor includes a dual ring wound retractor design described in U.S. patent application Ser. Nos. 12/873,115, and 12/119,414; U.S. Pat. Nos. 5,524,464, 7,238,154, 6,254,533, 6,814,078, 6,382,211, 8,021,296, and 8,012,088, among others. Generally, these devices are comprised of a cylindrical sheath disposed between a top and bottom ring. Shortening of the cylindrical sheath is generally effective to retract the wound opening, thereby permitting completion of a surgical procedure therethrough. It may be beneficial to combine fluid delivery and optionally fluid evacuation features with these devices to provide the advantages previously discussed above.
Such devices may provide better treatment of SSI, and preferably are easier to use, optimize fluid management within the surgical wound, and reduce manufacturing costs and complexity. At least some of these objectives will be met by the embodiments disclosed below.
2. Description of the Background Art
The follow U.S. Patent Applications and U.S. Patents are relevant to surgical retractors: Ser. Nos. 12/873,115; 12/119,414; U.S. Pat. Nos. 5,524,464; 7,238,154; 6,254,533; 6,814,078; 6,382,211; 8,021,296; and 8,012,088.